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Nov. 21, 2012 -- A product marketed to help keep babies safe while they sleep may have the opposite effect.

At least 13 infants have died since 1997 while lying in sleep positioners or sleep wedges, a new CDC report shows. The products often claim to reduce the risk of sudden infant death syndrome (SIDS).

Researchers found all but one of the deaths involved infants aged 3 months or less. Most of the infants were placed on their sides to sleep in the sleep positioner, and many were later found lying on their stomachs.

Most of the infants suffocated after rolling onto their stomachs from a side-facing position.

The FDA has never approved any infant sleep positioner to prevent or reduce the risk of SIDS.

Officials are urging parents to follow these safety steps:

Stop using sleep positioners. Using a sleep positioner to hold an infant on his or her back for sleep is dangerous and unnecessary.

Never put pillows, wedges, comforters, or quilts under an infant in a crib or bassinet.

Always put an infant to sleep on his or her back at night and at nap time to reduce the risk of SIDS.

A few infant sleep positioners have been cleared by the FDA to treat specific medical conditions, such as gastroesophageal reflux. Officials say these sleep positioners should only be used by prescription.

New Warning for Sleep Positioners

There are two main types of infant sleep positioners. One is a flat mat with a side bolster. The other is an inclined wedge mat with side bolsters.

The FDA and U.S. Consumer Product Safety Commission (CPSC) also issued a warning against the use of sleep positioners in 2010.

In this latest report, researchers from the CDC, FDA, and CPSC reviewed data on deaths related to infant sleep positioners from January 1997 to March 2011.

The results showed 13 deaths. The victims ranged in age from 21 days to 4 months.

Four of the infants had been born prematurely and three were one of a set of twins. Four of the 13 infants also had recent respiratory symptoms, such as a cold.

“At least nine of the infants were placed on their sides (and one prone), raising the concern that the 'back-to-sleep' message to position infants on their backs is either not being heard or not being followed,” researcher Brenda Lawrence, MD, of the FDA, writes in the CDC report.

The CPSC has also received dozens of reports of infants put to sleep on their backs or sides in positioners and later found in a potentially dangerous position.